/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.analysis;

import org.apache.solr.common.ResourceLoader;
import org.apache.solr.util.plugin.ResourceLoaderAware;
import org.apache.lucene.analysis.StopFilter;
import org.apache.lucene.analysis.StopAnalyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.CharArraySet;

import java.util.Map;
import java.util.Set;
import java.io.IOException;

/**
 * Factory for {@link KeepWordFilter}.
 * 
 * <pre class="prettyprint" >
 * &lt;fieldType name="text_keepword" class="solr.TextField" positionIncrementGap="100"&gt;
 *   &lt;analyzer&gt;
 *     &lt;tokenizer class="solr.WhitespaceTokenizerFactory"/&gt;
 *     &lt;filter class="solr.KeepWordFilterFactory" words="keepwords.txt" ignoreCase="false" enablePositionIncrements="false"/&gt;
 *   &lt;/analyzer&gt;
 * &lt;/fieldType&gt;
 * </pre>
 * 
 * @version $Id: KeepWordFilterFactory.java 1073810 2011-02-23 16:27:55Z koji $
 */
public class KeepWordFilterFactory extends BaseTokenFilterFactory implements
		ResourceLoaderAware {

	@Override
	public void init(Map<String, String> args) {
		super.init(args);
		assureMatchVersion();
	}

	public void inform(ResourceLoader loader) {
		String wordFiles = args.get("words");
		ignoreCase = getBoolean("ignoreCase", false);
		enablePositionIncrements = getBoolean("enablePositionIncrements", false);

		if (wordFiles != null) {
			try {
				words = getWordSet(loader, wordFiles, ignoreCase);
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
		}
	}

	private CharArraySet words;
	private boolean ignoreCase;
	private boolean enablePositionIncrements;

	/**
	 * Set the keep word list. NOTE: if ignoreCase==true, the words are expected
	 * to be lowercase
	 */
	public void setWords(Set<String> words) {
		this.words = new CharArraySet(luceneMatchVersion, words, ignoreCase);
	}

	public void setIgnoreCase(boolean ignoreCase) {
		if (words != null && this.ignoreCase != ignoreCase) {
			words = new CharArraySet(luceneMatchVersion, words, ignoreCase);
		}
		this.ignoreCase = ignoreCase;
	}

	public boolean isEnablePositionIncrements() {
		return enablePositionIncrements;
	}

	public boolean isIgnoreCase() {
		return ignoreCase;
	}

	public CharArraySet getWords() {
		return words;
	}

	public KeepWordFilter create(TokenStream input) {
		return new KeepWordFilter(enablePositionIncrements, input, words);
	}
}
